JPH0459943B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a plasma spraying apparatus for spraying a powder material such as ceramic onto a base material using a plasma flame from a spray gun. This invention relates to a device for controlling the supply of.

(Prior art) Conventionally, in this type of plasma spraying equipment,
A powder injection nozzle is provided near the injection port of a thermal spray gun for injecting plasma flame, and the powder injection nozzle and a supply means including a hopper for supplying the powder material to be thermally sprayed are connected to a supply pipe such as a hose. A control valve provided on the hopper side of the supply means controls the supply of powder material to the thermal spray gun in response to spraying and stopping operations of the thermal spray gun.

(Problem to be Solved by the Invention) However, in the case of the above structure, since the control valve is provided on the hopper side of the supply means, the supply of powder material to the thermal spray gun is stopped by the control valve. However, powder material remains in the supply pipe between the supply means and the powder injection nozzle of the thermal spray gun, so when the next thermal spray starts, the powder material remaining in the supply pipe will be removed. This type of plasma spraying has the problem that the powder material is injected all at once (see Figure 2 C), and the supply of powder material is instantaneous when the spray gun starts spraying. This caused various problems such as uneven supply.

The present invention is intended to solve the above-mentioned conventional drawbacks, and is to provide a powder in a plasma spraying apparatus that can reliably cope with the quantitative supply of powder material and the instantaneous supply of powder material at the start of thermal spraying to a thermal spray gun. The purpose of the present invention is to provide a material supply control device.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a thermal spray gun having an injection port for injecting plasma flame and a powder injection nozzle near the injection port, and a powder material to be sprayed. A plasma spraying apparatus comprising a means for supplying the powder material to a powder injection nozzle of the thermal spray gun, and for supplying the powder material to the powder injection nozzle of the thermal spray gun to spray the base material, the powder material supply means and the thermal spray gun. A switching valve is installed near the powder injection nozzle for a powder material supply path that connects the powder injection nozzle to the powder injection nozzle. switching control in conjunction with the thermal spraying operation of the thermal spray gun so as to form a passage that shuts off the powder material and returns it to the supply means side or another storage tank, and allows the flow of the powder material in the supply passage during non-thermal spraying. This is the configuration that will be used.

(Operation of the Invention) The switching valve is operated during the thermal spraying operation of the thermal spray gun, that is, during thermal spraying, and the switching valve allows communication between the supply path and the powder injection nozzle of the thermal spray gun. The powder is supplied to the powder injection nozzle of the thermal spray gun via the supply path. In addition, when the thermal spray gun is not spraying, the switching valve is operated to switch and communicate with the passage that blocks the passage and returns to the supply means, so that the powder material from the supply means is supplied to the powder injection nozzle. Instead, it is returned to the supply means side or another storage tank from within the supply path.

(Embodiment) Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. In the figure, 1 is a thermal spray gun equipped with a powder supply control switch (not shown) constituting one of the plasma spraying apparatuses. Then, DC power, plasma gas such as nitrogen and hydrogen, and cooling water are injected, and the plasma flame F is injected from the injection port 1a.
A powder injection nozzle 2 is mounted via a bracket 3, which is positioned substantially perpendicular to the powder injection nozzle. Further, a supply means 4 for supplying a powder material W to be thermally sprayed, such as ceramic, which constitutes one of the plasma spraying apparatuses, is attached to a hopper 5 that accommodates the powder material W and to the exit side of the hopper 5. supply amount adjustment device 6
and a carrier gas supply device 7 that supplies gas to transport the powder material W in the hopper 5, and the outlet side of the hopper 5 is connected to the powder injection nozzle 2 side of the thermal spray gun 1 by a hose or the like. They are connected via a supply path 8. Accordingly, the powder material W in the hopper 5 is turned on and off by the main switch (not shown) of the plasma spraying apparatus during the spraying operation.
The carrier gas is supplied into the supply path 8 by the carrier gas by the carrier gas supply device 7 controlled and driven by the carrier gas in the amount set by the supply amount adjusting device 6.

A switching valve 9 configured in a 2-position, 3-port type is incorporated in the supply path 8, and this switching valve 9 is mounted and fixed to the upper part of the bracket 3 near the powder injection nozzle 2 of the thermal spray gun 1. , the port a on the inlet side communicates with the supply path 8, one port b on the outlet side communicates with the powder injection nozzle 2, and the other port c communicates with the hopper 5 of the supply means 4. It communicates with the passage 10. The switching valve 9 is a double-acting cylinder operated by air, which is controlled by turning on or off a powder supply control switch provided in the thermal spraying gun 1 as the thermal spraying gun 1 sprays. The switching operation is configured to be performed. As the thermal spraying operation of the thermal spraying gun 1 is carried out, the switching valve 9 is controlled to switch, and this switching valve 9 allows communication between the supply passage 8 and the powder injection nozzle 2 during thermal spraying, and allows communication between the supply passage 8 and the powder injection nozzle 2 during non-thermal spraying. 8 and the powder injection nozzle 2, while allowing communication between the supply path 8 and the return path 10.

This embodiment is configured as described above,
Now, in the plasma spraying operation, when the main switch (not shown) in the plasma spraying apparatus is turned on, the supply amount adjusting device 6 and the carrier gas supplying device 7 are driven. The powder material W is constantly supplied into the supply path 8 by the carrier gas from the carrier gas supply device 7 in a constant amount set by the supply amount adjusting device 6. Therefore, when the thermal spraying operation by the thermal spraying gun 1 is started, the switching valve 9 is switched and controlled by a double-acting cylinder operated by air controlled by the "on" operation of the powder supply control switch activated during thermal spraying. Since the supply path 8 and the powder injection nozzle 2 are communicated with each other, the powder material W in the supply path 8 is fed by the carrier gas by the carrier gas supply device 7 at a constant rate set by the supply amount adjusting device 6. , is supplied into the powder injection nozzle 2 of the thermal spray gun 1 (see FIG. 2A). Then, the powder material W is transferred from the powder injection nozzle 2 to the injection port 1a of the thermal spray gun 1.
is injected near the front of the On the other hand, thermal spray gun 1
DC power, plasma gas, and even cooling water are injected into the , and plasma flame F is injected from the injection port 1 a of the thermal spray gun 1 . The powder material W that is sprayed and supplied near the front part is thermally sprayed onto a base material (not shown).

Perform the desired plasma spraying as described above,
After that, when the powder supply control switch is turned "off" to stop the operation, the double-acting cylinder operated by the air controlled by this operation (when not thermal spraying) turns the switching valve 9 in the opposite direction as described above. The switching control is performed to cut off the communication between the supply path 8 and the powder injection nozzle 2 and to connect the supply path 8 and the return path 10, so that the powder material W in the supply path 8 is transferred to the powder injection nozzle 2. It is returned to the hopper 5 of the supply means 4 via the return passage 10 without being supplied. (See Figure 2B) This return operation of the powder material W is performed while the supply amount adjusting device 6 and the carrier gas supply device 7 are being driven when the thermal spray gun 1 is not spraying, and is carried out for the next thermal spraying. It corresponds to this.

In this embodiment, a case has been described in which the return passage 10 is communicated with the hopper 5 of the supply means 4, but instead of this, a configuration may be adopted in which the return passage 10 is communicated with another storage tank (not shown).

(Effects of the Invention) As described in detail above, the present invention provides a thermal spray gun having an injection port for ejecting plasma flame and a powder injection nozzle near the injection port, and a powder material to be sprayed in the powder of the thermal spray gun. In a plasma spraying apparatus comprising a means for supplying the powder material to a spray nozzle, the powder material is supplied to the powder spray nozzle of the thermal spray gun for thermal spraying onto a base material, the supply means for the powder material and the powder spray nozzle of the thermal spray gun; A switching valve is installed in the vicinity of the powder injection nozzle for a powder material supply path that connects the This is because switching control is performed in conjunction with the thermal spraying operation of the thermal spray gun to form a passage that returns to the supply means side or to another storage tank, and to allow the flow of the powder material within the supply passage during non-thermal spraying. Unlike conventional methods, it is possible to eliminate powder material remaining between the supply means side and the powder injection nozzle during non-thermal spraying, so it is possible to always supply a fixed amount of powder material for each thermal spraying operation. At the same time, it is possible to reliably and smoothly respond to the instantaneous supply associated with the start of thermal spraying.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, in which FIG. 1 is a cross-sectional view of the main parts including the supply circuit, and FIGS. DESCRIPTION OF SYMBOLS 1... Thermal spray gun, 1a... Injection port, 2... Powder injection nozzle, 4... Supply means, 8... Supply path, 9
...Switching valve, 10...Return passage, W...Powder material.

Claims (1)

[Claims] 1 A thermal spray gun having an injection port for ejecting plasma flame and a powder injection nozzle near the injection port, and a means for supplying powder material to be sprayed to the powder injection nozzle of the thermal spray gun, In a plasma spraying apparatus that supplies a powder to a powder injection nozzle of a thermal spray gun to spray the base material, a powder injection nozzle is connected to a powder material supply path that connects the powder material supply means and the powder injection nozzle of the thermal spray gun. A switching valve is installed near the powder injection nozzle, and the switching valve forms a passage that allows communication from the supply passage to the powder injection nozzle, and a passage that blocks the passage and returns to the supply means side or another storage tank. A supply control device for powder material in a plasma spraying apparatus, characterized in that switching control is performed in conjunction with the thermal spraying operation of the thermal spray gun so as to allow the flow of the powder material in the supply path during non-thermal spraying.